The Studies On Preparation Technology And The Survival Properties Of Different Formulation Modalities Of Bifidobacterium

A combining method of microencapsulation technology with freeze-drying was adopted to improve the survival rate of Bifidobacterium in the process of production, transportation, storage and consuming. Meanwhile, the condition of cultivation and centrifugation, the screening of the high efficient protectants, and the preparation technology of microcapsules were studied. In addition, it was studied detailedly of the distintegrated characteristic of microcapsules under the harsh conditions and the storing characteristics were also discussed systematically and concretely. The main contents and results were as follows:1. The anaerobic culture method of Bifidobacterium was determined through orthogonal experiment: sodium hyposulfide was 3.0g, sodium bicarbonate was 3.0g, hydrogen-reducedir -on was 0.5g, water was 0.4mL in an airtight container of 1L.2. Base medium was determined to be TPY medium after having been screened. Then, The ingredient and dosage of medium were optimized by single factor experimentation and orthogonal design. The optimum culture was as follows: casein peptone was 1%, soy protein was 0.5%, yeast extract was 0.3%, stachyose was 0.2%, lactose was 0.1%, sucrose was 0.1%, on the basis of the base medium. The effect of the temperature and the pH value on the cell growth of Bifidobacterium was studied. The optimum condition to cultivate Bifidobacterium was that the best temperature was 37℃and the initial pH of culture medium was 6.5. According to the growth curve and the change of pH, the terminal time was about at 24 hours.3. The optimum centrifugation condition was 5000r/min for 10min at 4℃, and the highest rates of living cells were 98.7% for BLR(Bifidobacterium lactis) and 97.2% for BIY(Bifidobacterium infants).4. Four types of protectants were screened out. The results showed that the protectants were as follows: 10% synanthrin, 6% soy- protein, 12% fucose, 10% mannite for BLR, and 8% synanthrin, 8% soy protein, 12% fucose, 8% sucrose for BLR.5. An optimal method of preparation of microencapsulated by extrusion technique was screened out. As for BLR, the prime directions were as follows: sodium alginate was 3%, calcium chloride was 2%, hardening time was 60min, glue : bacterium was 1 : 1. And for the BIY the prime condition was as follows: sodium alginate was 3%, calcium chloride was 1%, hardening time was 40min, glue : bacterium was 1:1. The survival rates of bacterias were 71.2%(BLR) and 70.3%(BIY) by the the modifid method with protective additives. 6. An optimal method of preparation of microencapsulated by emulsification technique was screened out. The prime directions were as followed: sodium alginate was 3%, bacterium: glue was 1:1, emulsification time was 10min, stirring speed was 800r/min. The survival rates of bacterias were 71.9%(BLR) and 71.7%(BIY) by the modifid method with protective additives.7. Bifidobacterium microcapsules were prepared through spray-drying technique. Aracia gum andβ-cyclodextrin were chosen for the wall-materials. Four protectants(soy protein, sucrose, synanthrin and glycerin) and BLR were adopted as core-materials. Inlet air temperature and outlet air temperature were 130℃and 70—80℃. The temperature in the tower was 80℃and the temperature of the materials was 40℃. The recovery rate of the microcapsules was 57.8% and the relative survival rate of bacterias was 59.7%.8. Bifidobacterium microcapsules, which were prepared by several methods, had been disintegrated within 45min in simulated intestinal fluid. The result of using the simulated gastric fluid to treat the microcapsules which were prepared by a combining method of freeze-drying with emulsification for 4h showed that the survival rates of bacterias were 37.9%(BLR) and 40.6%(BIY). The survival rates were 68.1%(BLR) and 67.9%(BIY) when the microcapsules were treated in 0.3% bile salt solution for 3h, and the survival rates were 82.6%(BLR) and 82.1%(BIY) when treated in 6% NaCl solution for 12h. When treated in the environment at 65℃for 2h, the survival rates were 8.2%(BLR) and 8.1%(BIY). The microcapsules were stored at -18℃, 4℃, 20℃and 37℃for 180d and the best effect was showed when stored at -18℃, under which, the viable cell counts were 2.27×10~9cfu/g(BLR) and 2.14×10~9cfu/g(BIY). The microcapsules which were prepared by a combining method of freeze-drying with emulsification had better storage stabilization and toleration subjected to the harsh conditions.